CONNEXION OI' fVCLONJJS AM) KAINFALL WlTIi SUN-SPOTS. 2G7 



On Cyclone and Rainfall Periodicities in conneocion wiih the Sun-spot 

 Periodicity. By Ciiakles Melurum. 



[Printed n* extenso by the authority of the Council.] 



In continuation of the paper on this subject published in the Iteport for 1874 

 (pp. 218-240), 1 beg to submit the foUowiog brief discussion of the cj'clones 

 of the Indian Ocean, between the equator and 34° S., in the rears 1868-75, 

 and of the rainfall in different places from 1854 to 1872. 



Cyclones. 



The number of cyclones in each year, the positions of their centres at noon 

 on each day, their extent, duration, &c. have been approximately determined 

 in the way already described, and the results are given in Table I. 



From that and the similar Table given in 1874 we obtain the following 

 general results for the twenty years 1856-75 : — 



It will be seen that, on the whole, the number of cyclones increased from 

 1857 to 1862, decreased from 18G2 to 1867, then increased to 1870, and 

 again decreased to 1875. 



The distances traversed had nearly a similar progression, increasing from 

 1856 to 1861, decreasing from 1861 to 1867, then increasing to 1872, and 

 again decreasing to 1875. 



The areas have been determined by finding as nearly as possible the radii 



